New anatomical information on Araripesuchus buitreraensis with implications for the systematics of Uruguaysuchidae (Crocodyliforms, Notosuchia)

Abstract

Araripesuchus (Uruguaysuchidae) is a Gondwanan mesoeucrocodylian genus that includes several spe- cies, distributed in the Cretaceous of Niger (A. wegeneri and A. rattoides), Madagascar (A. tsangatsangana), Brazil (A. gomesii), and Argentina (A. patagonicus and A. buitreraensis). The two Argentinean species came from different localities of the lower Cenomanian of Patagonia. Here, we present a complete cranial description of A. buitreraensis and explore its phylogenetic relationships, based on new as well as pre- viously reported specimens. We studied the skulls of eight specimens of A. buitreraensis, almost all represented by partial cranium and mandible, adding new autapomorphies to the original diagnosis of this taxon. A comparison between the new specimens also reveals some discrepant features, which are interpreted as ontogeny or as intraspecific variation. We present revised scorings of several uruguay- suchid species (A. buitreraensis, A. gomesii, and Uruguaysuchus aznarezi) from a published morphological dataset and conduct a phylogenetic analysis to test the phylogenetic position of A. buitreraensis. As in resent phylogenetic proposals, this taxon was recovered as the basalmost member of a clade, which clusters all uruguaysuchids from South America. A revision of the diagnosis and a new phylogenetic definition of Uruguaysuchidae is also presented.